Verdigris is the common name for the chemical Cu(CH3COO)2, or Copper(II) acetate. It commonly occurs by the action of acetic acid when copper, brass or bronze is weathered and exposed to air or seawater over a period of time. Its name comes from the Middle English vertegrez, from the Old French verte grez, an alteration of vert-de-Grice — verd (green), de (of), and Grice (Greece)— "green of Greece".